[TASK] Cleanup "belog" sysext

Reformats the code, fixes indents and removes extra empty lines. This is
not a functional change but a visual clean up.

Change-Id: I0d11dd7c43eee5d181c4bc0565c85d651c5c29e1
Resolves: #45392
Releases: 6.0, 6.1
Reviewed-on: https://review.typo3.org/18207
Reviewed-by: Stefan Neufeind
Reviewed-by: Oliver Hader
Tested-by: Oliver Hader